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Yoo JS. Cellular Stress Responses against Coronavirus Infection: A Means of the Innate Antiviral Defense. J Microbiol Biotechnol 2024; 34:1-9. [PMID: 37674398 PMCID: PMC10840489 DOI: 10.4014/jmb.2307.07038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/20/2023] [Accepted: 09/06/2023] [Indexed: 09/08/2023]
Abstract
Cellular stress responses are crucial for maintaining cellular homeostasis. Stress granules (SGs), activated by eIF2α kinases in response to various stimuli, play a pivotal role in dealing with diverse stress conditions. Viral infection, as one kind of cellular stress, triggers specific cellular programs aimed at overcoming virus-induced stresses. Recent studies have revealed that virus-derived stress responses are tightly linked to the host's antiviral innate immunity. Virus infection-induced SGs act as platforms for antiviral sensors, facilitating the initiation of protective antiviral responses called "antiviral stress granules" (avSGs). However, many viruses, including coronaviruses, have evolved strategies to suppress avSG formation, thereby counteracting the host's immune responses. This review discusses the intricate relationship between cellular stress responses and antiviral innate immunity, with a specific focus on coronaviruses. Furthermore, the diverse mechanisms employed by viruses to counteract avSGs are described.
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Affiliation(s)
- Ji-Seung Yoo
- School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea
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2
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Wang XR, Cull B, Oliver JD, Kurtti TJ, Munderloh UG. The role of autophagy in tick-endosymbiont interactions: insights from Ixodes scapularis and Rickettsia buchneri. Microbiol Spectr 2024; 12:e0108623. [PMID: 38038450 PMCID: PMC10783069 DOI: 10.1128/spectrum.01086-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 10/27/2023] [Indexed: 12/02/2023] Open
Abstract
IMPORTANCE Ticks are second only to mosquitoes in their importance as vectors of disease agents; however, tick-borne diseases (TBDs) account for the majority of all vector-borne disease cases in the United States (approximately 76.5%), according to Centers for Disease Control and Prevention reports. Newly discovered tick species and their associated disease-causing pathogens, and anthropogenic and demographic factors also contribute to the emergence and re-emergence of TBDs. Thus, incorporating different tick control approaches based on a thorough knowledge of tick biology has great potential to prevent and eliminate TBDs in the future. Here we demonstrate that replication of a transovarially transmitted rickettsial endosymbiont depends on the tick's autophagy machinery but not on apoptosis. Our findings improve our understanding of the role of symbionts in tick biology and the potential to discover tick control approaches to prevent or manage TBDs.
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Affiliation(s)
- Xin-Ru Wang
- Department of Entomology, University of Minnesota, St. Paul, Minnesota, USA
- SUNY Center for Vector-Borne Diseases, Upstate Medical University, Syracuse, New York, USA
- Institute for Global Health and Translational Sciences, Upstate Medical University, Syracuse, New York, USA
- Department of Microbiology and Immunology, Upstate Medical University, Syracuse, New York, USA
| | - Benjamin Cull
- Department of Entomology, University of Minnesota, St. Paul, Minnesota, USA
| | - Jonathan D. Oliver
- Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Minneapolis, Minnesota, USA
| | - Timothy J. Kurtti
- Department of Entomology, University of Minnesota, St. Paul, Minnesota, USA
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Dernovics Á, Seprényi G, Rázga Z, Ayaydin F, Veréb Z, Megyeri K. Phenol-Soluble Modulin α3 Stimulates Autophagy in HaCaT Keratinocytes. Biomedicines 2023; 11:3018. [PMID: 38002017 PMCID: PMC10669503 DOI: 10.3390/biomedicines11113018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 10/30/2023] [Accepted: 11/07/2023] [Indexed: 11/26/2023] Open
Abstract
BACKGROUND Phenol-soluble modulins (PSMs) are pore-forming toxins (PFTs) produced by staphylococci. PSMs exert diverse cellular effects, including lytic, pro-apoptotic, pro-inflammatory and antimicrobial actions. Since the effects of PSMs on autophagy have not yet been reported, we evaluated the autophagic activity in HaCaT keratinocytes treated with recombinant PSMα3. METHODS The autophagic flux and levels of autophagic marker proteins were determined using Western blot analysis. Subcellular localization of LC3B and Beclin-1 was investigated using an indirect immunofluorescence assay. The ultrastructural features of control and PSMα3-treated cells were evaluated via transmission electron microscopy. Cytoplasmic acidification was measured via acridine orange staining. Phosphorylation levels of protein kinases, implicated in autophagy regulation, were studied using a phospho-kinase array and Western blot analysis. RESULTS PSMα3 facilitated the intracellular redistribution of LC3B, increased the average number of autophagosomes per cell, promoted the development of acidic vesicular organelles, elevated the levels of LC3B-II, stimulated autophagic flux and triggered a significant decrease in the net autophagic turnover rate. PSMα3 induced the accumulation of autophagosomes/autolysosomes, amphisomes and multilamellar bodies at the 0.5, 6 and 24 h time points, respectively. The phospho-Akt1/2/3 (T308 and S473), and phospho-mTOR (S2448) levels were decreased, whereas the phospho-Erk1/2 (T202/Y204 and T185/Y187) level was increased in PSMα3-treated cells. CONCLUSIONS In HaCaT keratinocytes, PSMα3 stimulates autophagy. The increased autophagic activity elicited by sub-lytic PSM concentrations might be an integral part of the cellular defense mechanisms protecting skin homeostasis.
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Affiliation(s)
- Áron Dernovics
- Department of Medical Microbiology, Albert Szent-Györgyi Medical School, University of Szeged, Dóm tér 10., H-6720 Szeged, Hungary;
| | - György Seprényi
- Department of Anatomy, Histology and Embryology, Albert Szent-Györgyi Medical School, University of Szeged, Kossuth L. sgt. 40., H-6724 Szeged, Hungary;
| | - Zsolt Rázga
- Department of Pathology, University of Szeged, Állomás u. 2, H-6720 Szeged, Hungary;
| | - Ferhan Ayaydin
- Hungarian Centre of Excellence for Molecular Medicine (HCEMM) Nonprofit Ltd., Római krt. 21., H-6723 Szeged, Hungary;
- Laboratory of Cellular Imaging, Biological Research Centre, Eötvös Loránd Research Network, Temesvári krt. 62., H-6726 Szeged, Hungary
| | - Zoltán Veréb
- Regenerative Medicine and Cellular Pharmacology Laboratory, Department of Dermatology and Allergology, University of Szeged, Korányi Fasor 6, H-6720 Szeged, Hungary;
- Biobank, University of Szeged, H-6720 Szeged, Hungary
- Interdisciplinary Research Development and Innovation Center of Excellence, University of Szeged, H-6720 Szeged, Hungary
| | - Klára Megyeri
- Department of Medical Microbiology, Albert Szent-Györgyi Medical School, University of Szeged, Dóm tér 10., H-6720 Szeged, Hungary;
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Seeger AY, Zaidi F, Alhayek S, Jones RM, Zohair H, Holland RL, Kim IJ, Blanke SR. Host cell sensing and restoration of mitochondrial function and metabolism within Helicobacter pylori VacA intoxicated cells. mBio 2023; 14:e0211723. [PMID: 37815365 PMCID: PMC10653863 DOI: 10.1128/mbio.02117-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 08/23/2023] [Indexed: 10/11/2023] Open
Abstract
IMPORTANCE Persistent human gastric infection with Helicobacter pylori is the single most important risk factor for development of gastric malignancy, which is one of the leading causes of cancer-related deaths worldwide. An important virulence factor for Hp colonization and severity of gastric disease is the protein exotoxin VacA, which is secreted by the bacterium and modulates functional properties of gastric cells. VacA acts by damaging mitochondria, which impairs host cell metabolism through impairment of energy production. Here, we demonstrate that intoxicated cells have the capacity to detect VacA-mediated damage, and orchestrate the repair of mitochondrial function, thereby restoring cellular health and vitality. This study provides new insights into cellular recognition and responses to intracellular-acting toxin modulation of host cell function, which could be relevant for the growing list of pathogenic microbes and viruses identified that target mitochondria as part of their virulence strategies.
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Affiliation(s)
- Ami Y. Seeger
- Department of Microbiology, University of Illinois, Urbana, Illinois, USA
| | - Faisal Zaidi
- Department of Microbiology, University of Illinois, Urbana, Illinois, USA
| | - Sammy Alhayek
- Department of Microbiology, University of Illinois, Urbana, Illinois, USA
| | - Rachel M. Jones
- Department of Microbiology, University of Illinois, Urbana, Illinois, USA
| | - Huzaifa Zohair
- Department of Microbiology, University of Illinois, Urbana, Illinois, USA
| | - Robin L. Holland
- Department of Pathobiology, University of Illinois, Urbana, Illinois, USA
| | - Ik-Jung Kim
- Department of Microbiology, University of Illinois, Urbana, Illinois, USA
- Buck Institute for Research on Aging, Novato, California, USA
| | - Steven R. Blanke
- Department of Microbiology, University of Illinois, Urbana, Illinois, USA
- Department of Pathobiology, University of Illinois, Urbana, Illinois, USA
- Department of Biomedical and Translational Medicine, University of Illinois, Urbana, Illinois, USA
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5
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Fraschilla I, Evavold CL. Biting the hand that feeds: Metabolic determinants of cell fate during infection. Front Immunol 2022; 13:923024. [DOI: 10.3389/fimmu.2022.923024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 09/14/2022] [Indexed: 11/13/2022] Open
Abstract
Metabolic shifts can occur in cells of the innate immune system in response to microbial infection. Whether these metabolic shifts benefit host defense and propagation of an immune response appears to be context dependent. In an arms race, host-adapted microbes and mammalian cells vie for control of biosynthetic machinery, organelles, and metabolites. Herein, we discuss the intersection of host metabolism and cell-intrinsic immunity with implications for cell fate during infection. Sensation of microbial ligands in isolation results in host metabolic shifts that imbues normal innate immune function, such as cytokine secretion. However, living microbes have an arsenal of effectors and strategies to subvert cell-intrinsic immune responses by manipulating host metabolism. Consequently, host metabolism is monitored as an indicator of invasion or manipulation by a pathogen, primarily through the actions of guard proteins and inflammasome pathways. In this review, we frame initiation of cell-intrinsic immunity in the context of host metabolism to include a physiologic “Goldilocks zone” of allowable shifts with guard circuits monitoring wide perturbations away from this zone for the initiation of innate immune responses. Through comparison of studies with purified microbial ligands, dead microbes, and live pathogens we may begin to understand how shifts in metabolism determine the outcome of host-pathogen interactions.
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Ju S, Chen H, Wang S, Lin J, Ma Y, Aroian RV, Peng D, Sun M. C. elegans monitor energy status via the AMPK pathway to trigger innate immune responses against bacterial pathogens. Commun Biol 2022; 5:643. [PMID: 35773333 PMCID: PMC9246835 DOI: 10.1038/s42003-022-03589-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Pathogen recognition and the triggering of host innate immune system are critical to understanding pathogen-host interaction. Cellular surveillance systems have been identified as an important strategy for the identification of microbial infection. In the present study, using Bacillus thuringiensis-Caenorhabditis elegans as a model, we found an approach for surveillance systems to sense pathogens. We report that Bacillus thuringiensis Cry5Ba, a typical pore-forming toxin, caused mitochondrial damage and energy imbalance by triggering potassium ion leakage, instead of directly targeting mitochondria. Interestingly, we find C. elegans can monitor intracellular energy status to trigger innate immune responses via AMP-activated protein kinase (AMPK), secreting multiple effectors to defend against pathogenic attacks. Our study indicates that the imbalance of energy status is a prevalent side effect of pathogen infection. Furthermore, the AMPK-dependent surveillance system may serve as a practicable strategy for the host to recognize and defense against pathogens. Bacillus thuringiensis toxin Cry5Ba triggers potassium ion leakage, causing mitochondrial damage and energy imbalance. C. elegans can monitor this intracellular energy imbalance via AMP-activated protein kinase to trigger innate immune responses.
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Affiliation(s)
- Shouyong Ju
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, National Engineering Research Center of Microbial Pesticides, Huazhong Agricultural University, Wuhan, 430070, China
| | - Hanqiao Chen
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, National Engineering Research Center of Microbial Pesticides, Huazhong Agricultural University, Wuhan, 430070, China
| | - Shaoying Wang
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, National Engineering Research Center of Microbial Pesticides, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jian Lin
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, National Engineering Research Center of Microbial Pesticides, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yanli Ma
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, National Engineering Research Center of Microbial Pesticides, Huazhong Agricultural University, Wuhan, 430070, China
| | - Raffi V Aroian
- Program in Molecular Medicine, University of Massachusetts Chan Medical School Worcester, Worcester, MA, 01605-2377, USA
| | - Donghai Peng
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, National Engineering Research Center of Microbial Pesticides, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, National Engineering Research Center of Microbial Pesticides, Huazhong Agricultural University, Wuhan, 430070, China.
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Smyth R, Sun J. Protein Kinase R in Bacterial Infections: Friend or Foe? Front Immunol 2021; 12:702142. [PMID: 34305942 PMCID: PMC8297547 DOI: 10.3389/fimmu.2021.702142] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/28/2021] [Indexed: 12/28/2022] Open
Abstract
The global antimicrobial resistance crisis poses a significant threat to humankind in the coming decades. Challenges associated with the development of novel antibiotics underscore the urgent need to develop alternative treatment strategies to combat bacterial infections. Host-directed therapy is a promising new therapeutic strategy that aims to boost the host immune response to bacteria rather than target the pathogen itself, thereby circumventing the development of antibiotic resistance. However, host-directed therapy depends on the identification of druggable host targets or proteins with key functions in antibacterial defense. Protein Kinase R (PKR) is a well-characterized human kinase with established roles in cancer, metabolic disorders, neurodegeneration, and antiviral defense. However, its role in antibacterial defense has been surprisingly underappreciated. Although the canonical role of PKR is to inhibit protein translation during viral infection, this kinase senses and responds to multiple types of cellular stress by regulating cell-signaling pathways involved in inflammation, cell death, and autophagy – mechanisms that are all critical for a protective host response against bacterial pathogens. Indeed, there is accumulating evidence to demonstrate that PKR contributes significantly to the immune response to a variety of bacterial pathogens. Importantly, there are existing pharmacological modulators of PKR that are well-tolerated in animals, indicating that PKR is a feasible target for host-directed therapy. In this review, we provide an overview of immune cell functions regulated by PKR and summarize the current knowledge on the role and functions of PKR in bacterial infections. We also review the non-canonical activators of PKR and speculate on the potential mechanisms that trigger activation of PKR during bacterial infection. Finally, we provide an overview of existing pharmacological modulators of PKR that could be explored as novel treatment strategies for bacterial infections.
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Affiliation(s)
- Robin Smyth
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Jim Sun
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada.,Centre for Infection, Immunity and Inflammation, University of Ottawa, Ottawa, ON, Canada
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8
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Vozza EG, Mulcahy ME, McLoughlin RM. Making the Most of the Host; Targeting the Autophagy Pathway Facilitates Staphylococcus aureus Intracellular Survival in Neutrophils. Front Immunol 2021; 12:667387. [PMID: 34220813 PMCID: PMC8242348 DOI: 10.3389/fimmu.2021.667387] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 05/28/2021] [Indexed: 12/21/2022] Open
Abstract
The success of Staphylococcus aureus as a human commensal and an opportunistic pathogen relies on its ability to adapt to several niches within the host. The innate immune response plays a key role in protecting the host against S. aureus infection; however, S. aureus adeptness at evading the innate immune system is indisputably evident. The “Trojan horse” theory has been postulated to describe a mechanism by which S. aureus takes advantage of phagocytes as a survival niche within the host to facilitate dissemination of S. aureus to secondary sites during systemic infection. Several studies have determined that S. aureus can parasitize both professional and non-professional phagocytes by manipulating the host autophagy pathway in order to create an intracellular survival niche. Neutrophils represent a critical cell type in S. aureus infection as demonstrated by the increased risk of infection among patients with congenital neutrophil disorders. However, S. aureus has been repeatedly shown to survive intracellularly within neutrophils with evidence now supporting a pathogenic role of host autophagy. By manipulating this pathway, S. aureus can also alter the apoptotic fate of the neutrophil and potentially skew other important signalling pathways for its own gain. Understanding these critical host-pathogen interactions could lead to the development of new host directed therapeutics for the treatment of S. aureus infection by removing its intracellular niche and restoring host bactericidal functions. This review discusses the current findings surrounding intracellular survival of S. aureus within neutrophils, the pathogenic role autophagy plays in this process and considers the therapeutic potential for targeting this immune evasion mechanism.
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Affiliation(s)
- Emilio G Vozza
- Host-Pathogen Interactions Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Michelle E Mulcahy
- Host-Pathogen Interactions Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Rachel M McLoughlin
- Host-Pathogen Interactions Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
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9
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Tweedie A, Nissan T. Hiding in Plain Sight: Formation and Function of Stress Granules During Microbial Infection of Mammalian Cells. Front Mol Biosci 2021; 8:647884. [PMID: 33996904 PMCID: PMC8116797 DOI: 10.3389/fmolb.2021.647884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/01/2021] [Indexed: 01/21/2023] Open
Abstract
Stress granule (SG) formation is a host cell response to stress-induced translational repression. SGs assemble with RNA-binding proteins and translationally silent mRNA. SGs have been demonstrated to be both inhibitory to viruses, as well as being subverted for viral roles. In contrast, the function of SGs during non-viral microbial infections remains largely unexplored. A handful of microbial infections have been shown to result in host SG assembly. Nevertheless, a large body of evidence suggests SG formation in hosts is a widespread response to microbial infection. Diverse stresses caused by microbes and their products can activate the integrated stress response in order to inhibit translation initiation through phosphorylation of the eukaryotic translation initiation factor 2α (eIF2α). This translational response in other contexts results in SG assembly, suggesting that SG assembly can be a general phenomenon during microbial infection. This review explores evidence for host SG formation in response to bacterial, fungal, and protozoan infection and potential functions of SGs in the host and for adaptations of the pathogen.
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Affiliation(s)
- Alistair Tweedie
- Department of Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Tracy Nissan
- Department of Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Brighton, United Kingdom.,Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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Abstract
In its natural habitat, C. elegans encounters a wide variety of microbes, including food, commensals and pathogens. To be able to survive long enough to reproduce, C. elegans has developed a complex array of responses to pathogens. These activities are coordinated on scales that range from individual organelles to the entire organism. Often, the response is triggered within cells, by detection of infection-induced damage, mainly in the intestine or epidermis. C. elegans has, however, a capacity for cell non-autonomous regulation of these responses. This frequently involves the nervous system, integrating pathogen recognition, altering host biology and governing avoidance behavior. Although there are significant differences with the immune system of mammals, some mechanisms used to limit pathogenesis show remarkable phylogenetic conservation. The past 20 years have witnessed an explosion of host-pathogen interaction studies using C. elegans as a model. This review will discuss the broad themes that have emerged and highlight areas that remain to be fully explored.
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Affiliation(s)
- Céline N Martineau
- Aix Marseille Université, Inserm, CNRS, CIML, Turing Centre for Living Systems, Marseille, France
| | | | - Nathalie Pujol
- Aix Marseille Université, Inserm, CNRS, CIML, Turing Centre for Living Systems, Marseille, France.
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11
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Yang Y, Huang X, Yuan W, Xiang Y, Guo X, Wei W, Soberón M, Bravo A, Liu K. Bacillus thuringiensis cry toxin triggers autophagy activity that may enhance cell death. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2021; 171:104728. [PMID: 33357550 DOI: 10.1016/j.pestbp.2020.104728] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/09/2020] [Accepted: 10/10/2020] [Indexed: 06/12/2023]
Abstract
Although it is well known that Bacillus thuringiensis Cry toxins kill insect pest by disrupting midgut cells of susceptible larvae through their pore formation activity, it is not clear what intracellular events are triggered after pore formation on the cell membrane of the target cells. Here we analyzed the role of Cry toxins on autophagy activation using several cell lines as models as well as in Helicoverpa armigera larvae. The selected insect cell lines (Hi5, Sl-HP and Sf9) were susceptible to activated Cry1Ca toxin, but only Sl-HP cells were also susceptible to activated Cry1Ac toxin. In contrast, the mammalian cell line 293 T was not susceptible to Cry1Ac or to Cry1Ca. Results show that Cry toxins induced autophagy only in the susceptible cell lines as shown by the analysis of the changes in the ratio of Atg8-PE to Atg8 and by formation of autophagosome dots containing Atg8-PE. The Cry1Ac enhanced autophagy in the midgut tissue of H. armigera larvae. Silencing expression of specific genes by RNAi assays confirmed that the autophagy induced by activated Cry toxins was dependent on AMPK and JNK pathways. Finally, inhibition of autophagy in the cell lines by specific inhibitors or RNAi assays resulted in delayed cell death triggered by Cry toxins, suggesting that the increased autophagy activity observed after toxin intoxication may contribute to cell death.
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Affiliation(s)
- Yongbo Yang
- School of Life Sciences, Central China Normal University, Wuhan 430070, China
| | - Xiaoying Huang
- School of Life Sciences, Central China Normal University, Wuhan 430070, China
| | - Wanli Yuan
- School of Life Sciences, Central China Normal University, Wuhan 430070, China
| | - Yang Xiang
- School of Life Sciences, Central China Normal University, Wuhan 430070, China
| | - Xueqin Guo
- School of Life Sciences, Central China Normal University, Wuhan 430070, China
| | - Wei Wei
- School of Life Sciences, Central China Normal University, Wuhan 430070, China
| | - Mario Soberón
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Alejandra Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Kaiyu Liu
- School of Life Sciences, Central China Normal University, Wuhan 430070, China,.
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12
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Fiedler SA, Boller K, Junker AC, Kamp C, Hilger A, Schwarz W, Seitz R, Salge-Bartels U. Evaluation of the in vitro Function of Platelet Concentrates from Pooled Buffy Coats or Apheresis. Transfus Med Hemother 2020; 47:314-324. [PMID: 32884504 DOI: 10.1159/000504917] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 11/19/2019] [Indexed: 11/19/2022] Open
Abstract
Background Platelet concentrates play an important role in transfusion medicine. Their short lifespan and lack of robustness require efforts to ensure adequate product quality. In this study, we compared the in vitro quality of the main concentrate types, pooled platelet concentrate (PPC) from whole blood donations, and platelet concentrate from single-donor apheresis (APC). Methods Twenty PPCs and 20 APCs prepared in plasma were analyzed on days 2, 4, and 7 of storage. Variables related to metabolism, degranulation, platelet aggregation, P-selectin expression, and annexin V binding were analyzed. Morphology was assessed by transmission electron microscopy of ultrathin sections. A microfluidic device was applied to test the effects of shear stress on platelet function. Results The metabolic parameters indicated stable storage conditions throughout the 7-day period. The resting discoid form was the prevailing morphology on days 2 and 4 in the PPCs and APCs. Chemokine release and receptor shedding of soluble P-selectin and soluble CD40L equally increased in PPCs and APCs. Aggregation responses to ADP and collagen were heterogeneous, with marked losses in collagen responsiveness on day 4 in individual concentrates. Baseline expression of P-selectin in PPCs and APCs was low, and inducibility of P-selectin was well preserved until day 4. Under shear stress, equal adhesiveness and stability were found with platelets from PPCs and APCs. Conclusions Platelets from PPCs and APCs showed similar in vitro function and stability parameters. However, platelet concentrates presented a high variability and individual concentrates an impaired functional capability. Identifying the factors contributing to this would help increase product reliability.
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Affiliation(s)
- Sarah Anna Fiedler
- Division of Hematology/Transfusion Medicine, Paul-Ehrlich-Institut, Langen, Germany
| | - Klaus Boller
- Division of Immunology, Paul-Ehrlich-Institut, Langen, Germany
| | - Ann-Christine Junker
- Division of Hematology/Transfusion Medicine, Paul-Ehrlich-Institut, Langen, Germany
| | - Christel Kamp
- Division of Microbiology, Paul-Ehrlich-Institut, Langen, Germany
| | - Anneliese Hilger
- Division of Hematology/Transfusion Medicine, Paul-Ehrlich-Institut, Langen, Germany
| | - Wolfgang Schwarz
- Division of Hematology/Transfusion Medicine, Paul-Ehrlich-Institut, Langen, Germany
| | - Rainer Seitz
- Division of Hematology/Transfusion Medicine, Paul-Ehrlich-Institut, Langen, Germany
| | - Ursula Salge-Bartels
- Division of Hematology/Transfusion Medicine, Paul-Ehrlich-Institut, Langen, Germany
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Kumar A, Rahal A, Sohal JS, Gupta VK. Bacterial stress response: understanding the molecular mechanics to identify possible therapeutic targets. Expert Rev Anti Infect Ther 2020; 19:121-127. [PMID: 32811215 DOI: 10.1080/14787210.2020.1813021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Bacteria are ubiquitous and many of them are pathogenic in nature. Entry of bacteria in host and its recognition by host defense system induce stress in host cells. With time, bacteria have also developed strategies including drug resistance to escape from antibacterial therapy as well as host defense mechanism. AREAS COVERED Bacterial stress initiates and promotes adaptive immune response through several integrated mechanisms. The mechanisms of bacteria to up and down regulate different pathways involved in these responses have been discussed. The genetic expression of these pathways can be manipulated by the pharmacological interventions. Present review discusses in these contexts and explores the possibilities to overcome stress induced by bacterial pathogens and to suggest new possible therapeutic targets. EXPERT OPINION In our opinion, there are two important fronts to regulate the bacterial stress. One is to target caspase involved in the process of transformation and translation at gene level and protein expression. Second is the identification of bacterial genes that lead to synthesis of abnormal end products supporting bacterial survival in host environment and also to surpass the host defense mechanism. Identification of such genes and their expression products could be an effective option to encounter bacterial resistance.
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Affiliation(s)
- Amit Kumar
- College of Biotechnology, SVPUAT , Meerut, India
| | - Anu Rahal
- Division of Animal Health, ICAR- CIRG , Mathura, India
| | - Jagdip Singh Sohal
- Amity University Jaipur, Centre for Mycobacterial Disease Research, Amity University , Jaipur, India
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Interaction of Macrophages and Cholesterol-Dependent Cytolysins: The Impact on Immune Response and Cellular Survival. Toxins (Basel) 2020; 12:toxins12090531. [PMID: 32825096 PMCID: PMC7551085 DOI: 10.3390/toxins12090531] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/13/2020] [Accepted: 08/15/2020] [Indexed: 02/07/2023] Open
Abstract
Cholesterol-dependent cytolysins (CDCs) are key virulence factors involved in many lethal bacterial infections, including pneumonia, necrotizing soft tissue infections, bacterial meningitis, and miscarriage. Host responses to these diseases involve myeloid cells, especially macrophages. Macrophages use several systems to detect and respond to cholesterol-dependent cytolysins, including membrane repair, mitogen-activated protein (MAP) kinase signaling, phagocytosis, cytokine production, and activation of the adaptive immune system. However, CDCs also promote immune evasion by silencing and/or destroying myeloid cells. While there are many common themes between the various CDCs, each CDC also possesses specific features to optimally benefit the pathogen producing it. This review highlights host responses to CDC pathogenesis with a focus on macrophages. Due to their robust plasticity, macrophages play key roles in the outcome of bacterial infections. Understanding the unique features and differences within the common theme of CDCs bolsters new tools for research and therapy.
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15
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King BC, Kulak K, Colineau L, Blom AM. Outside in: Roles of complement in autophagy. Br J Pharmacol 2020; 178:2786-2801. [PMID: 32621514 DOI: 10.1111/bph.15192] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/17/2020] [Accepted: 06/24/2020] [Indexed: 12/12/2022] Open
Abstract
The complement system is a well-characterized cascade of extracellular serum proteins that is activated by pathogens and unwanted waste material. Products of activated complement signal to the host cells via cell surface receptors, eliciting responses such as removal of the stimulus by phagocytosis. The complement system therefore functions as a warning system, resulting in removal of unwanted material. This review describes how extracellular activation of the complement system can also trigger autophagic responses within cells, up-regulating protective homeostatic autophagy in response to perceived stress, but also initiating targeted anti-microbial autophagy in order to kill intracellular cytoinvasive pathogens. In particular, we will focus on recent discoveries that indicate that complement may also have roles in detection and autophagy-mediated disposal of unwanted materials within the intracellular environment. We therefore summarize the current evidence for complement involvement in autophagy, both by transducing signals across the cell membrane, as well as roles within the cellular environment. LINKED ARTICLES: This article is part of a themed issue on Canonical and non-canonical functions of the complement system in health and disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.14/issuetoc.
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Affiliation(s)
- Ben C King
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Klaudia Kulak
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Lucie Colineau
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Anna M Blom
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
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16
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Sanchez-Garrido J, Shenoy AR. Regulation and repurposing of nutrient sensing and autophagy in innate immunity. Autophagy 2020; 17:1571-1591. [PMID: 32627660 PMCID: PMC8354595 DOI: 10.1080/15548627.2020.1783119] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Nutrients not only act as building blocks but also as signaling molecules. Nutrient-availability promotes cell growth and proliferation and suppresses catabolic processes, such as macroautophagy/autophagy. These effects are mediated by checkpoint kinases such as MTOR (mechanistic target of rapamycin kinase), which is activated by amino acids and growth factors, and AMP-activated protein kinase (AMPK), which is activated by low levels of glucose or ATP. These kinases have wide-ranging activities that can be co-opted by immune cells upon exposure to danger signals, cytokines or pathogens. Here, we discuss recent insight into the regulation and repurposing of nutrient-sensing responses by the innate immune system during infection. Moreover, we examine how natural mutations and pathogen-mediated interventions can alter the balance between anabolic and autophagic pathways leading to a breakdown in tissue homeostasis and/or host defense.Abbreviations: AKT1/PKB: AKT serine/threonine kinase 1; ATG: autophagy related; BECN1: beclin 1; CGAS: cyclic GMP-AMP synthase; EIF2AK4/GCN2: eukaryotic translation initiation factor 2 alpha kinase 4; ER: endoplasmic reticulum; FFAR: free fatty acid receptor; GABARAP: GABA type A receptor-associated protein; IFN: interferon; IL: interleukin; LAP: LC3-associated phagocytosis; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MAP3K7/TAK1: mitogen-activated protein kinase kinase kinase 7; MAPK: mitogen-activated protein kinase; MTOR: mechanistic target of rapamycin kinase; NLR: NOD (nucleotide-binding oligomerization domain) and leucine-rich repeat containing proteins; PI3K, phosphoinositide 3-kinase; PRR: pattern-recognition receptor; PtdIns3K: phosphatidylinositol 3-kinase; RALB: RAS like proto-oncogene B; RHEB: Ras homolog, MTORC1 binding; RIPK1: receptor interacting serine/threonine kinase 1; RRAG: Ras related GTP binding; SQSTM1/p62: sequestosome 1; STING1/TMEM173: stimulator of interferon response cGAMP interactor 1; STK11/LKB1: serine/threonine kinase 11; TBK1: TANK binding kinase 1; TLR: toll like receptor; TNF: tumor necrosis factor; TRAF6: TNF receptor associated factor 6; TRIM: tripartite motif protein; ULK1: unc-51 like autophagy activating kinase 1; V-ATPase: vacuolar-type H+-proton-translocating ATPase.
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Affiliation(s)
- Julia Sanchez-Garrido
- Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Avinash R Shenoy
- Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK.,Satellite Group Leader, The Francis Crick Institute, London, UK
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17
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von Hoven G, Qin Q, Neukirch C, Husmann M, Hellmann N. Staphylococcus aureus α-toxin: small pore, large consequences. Biol Chem 2020; 400:1261-1276. [PMID: 30951494 DOI: 10.1515/hsz-2018-0472] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 03/26/2019] [Indexed: 12/14/2022]
Abstract
The small β-pore-forming α-toxin, also termed α-hemolysin or Hla is considered to be an important virulence factor of Staphylococcus aureus. Perforation of the plasma membrane (PM) by Hla leads to uncontrolled flux of ions and water. Already a small number of toxin pores seems to be sufficient to induce complex cellular responses, many of which depend on the efflux of potassium. In this article, we discuss the implications of secondary membrane lesions, for example, by endogenous channels, for Hla-mediated toxicity, for calcium-influx and membrane repair. Activation of purinergic receptors has been proposed to be a major contributor to the lytic effects of various pore forming proteins, but new findings raise doubts that this holds true for Hla. However, the recently discovered cellular pore forming proteins gasdermin D and Mixed lineage kinase domain-like pseudokinase (MLKL) which perforate the PM from the cytosolic side might contribute to both calcium-influx-dependent damage and membrane repair. Activation of endogenous pore forming proteins by Hla above a threshold concentration could explain the apparent dependence of pore characteristics on toxin concentrations. If secondary membrane damage in the aftermath of Hla-attack contributes significantly to overall PM permeability, it might be an interesting target for new therapeutic approaches.
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Affiliation(s)
- Gisela von Hoven
- Institute of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg-University Mainz, Obere Zahlbacher Straße 67, 55131 Mainz, Germany
| | - Qianqian Qin
- Institute of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg-University Mainz, Obere Zahlbacher Straße 67, 55131 Mainz, Germany
| | - Claudia Neukirch
- Institute of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg-University Mainz, Obere Zahlbacher Straße 67, 55131 Mainz, Germany
| | - Matthias Husmann
- Institute of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg-University Mainz, Obere Zahlbacher Straße 67, 55131 Mainz, Germany
| | - Nadja Hellmann
- Institute for Pharmacy and Biochemistry, Johannes Gutenberg-University Mainz, Johann-Joachim Becher-Weg 30, 55128 Mainz, Germany
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Wang Z, Zhou H, Zheng H, Zhou X, Shen G, Teng X, Liu X, Zhang J, Wei X, Hu Z, Zeng F, Hu Y, Hu J, Wang X, Chen S, Cheng J, Zhang C, Gui Y, Zou S, Hao Y, Zhao Q, Wu W, Zhou Y, Cui K, Huang N, Wei Y, Li W, Li J. Autophagy-based unconventional secretion of HMGB1 by keratinocytes plays a pivotal role in psoriatic skin inflammation. Autophagy 2020; 17:529-552. [PMID: 32019420 DOI: 10.1080/15548627.2020.1725381] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The precise mechanism through which macroautophagy/autophagy affects psoriasis is poorly understood. Here, we found that keratinocyte (KC) autophagy, which was positively correlated with psoriatic severity in patients and mouse models and could be inhibited by mitogen-activated protein kinase (MAPK) family inactivation. The impairment of autophagic flux alleviated psoriasisform inflammation. We also found that an autophagy-based unconventional secretory pathway (autosecretion) dependent on ATG5 (autophagy related 5) and GORASP2 (golgi reassembly stacking protein 2) promoted psoriasiform KC inflammation. Moreover, the alarmin HMGB1 (high mobility group box 1) was more effective than other autosecretory proteins in regulating psoriasiform cutaneous inflammation. HMGB1 neutralization in autophagy-efficient KCs eliminated the differences in psoriasiform inflammation between Krt14+/+-Atg5f/f KCs and Krt14Cre/+-atg5f/f KCs, and conversely, recombinant HMGB1 almost completely restored psoriasiform inflammation in Krt14Cre/+-atg5f/f KCs in vivo. These results suggest that HMGB1-associated autosecretion plays a pivotal role in cutaneous inflammation. Finally, we demonstrated that Krt14Cre/+-hmgb1f/f mice displayed attenuated psoriatic inflammation due to the essential crosstalk between KC-specific HMGB1-associated autosecretion and γδT cells. Thus, this study uncovered a novel autophagy mechanism in psoriasis pathogenesis, and the findings imply the clinical significance of investigating and treating psoriasis.Abbreviations: 3-MA: 3-methyladenine; ACTB: actin beta; AGER: advanced glycosylation end-product specific receptor; Anti-HMGB1: anti-HMGB1 neutralizing antibody; Anti-IL18: anti-IL18 neutralizing antibody; Anti-IL1B: anti-IL1B neutralizing antibody; ATG5: autophagy related 5; BAF: bafilomycin A1; BECN1: beclin 1; CASP1: caspase 1; CCL: C-C motif chemokine ligand; CsA: cyclosporine A; ctrl shRNA: lentivirus harboring shRNA against control; CXCL: C-X-C motif chemokine ligand; DCs: dendritic cells; DMEM: dulbecco's modified Eagle's medium; ELISA: enzyme-linked immunosorbent assay; EM: electron microscopy; FBS: fetal bovine serum; GORASP2 shRNA: lentivirus harboring shRNA against GORASP2; GORASP2/GRASP55: golgi reassembly stacking protein 2; GR1: a composite epitope between LY6 (lymphocyte antigen 6 complex) locus C1 and LY6 locus G6D antigens; H&E: hematoxylin and eosin; HMGB1: high mobility group box 1; HMGB1 shRNA: lentivirus harboring shRNA against HMGB1; IFNG/IFN-γ: interferon gamma; IL17A: interleukin 17A; IL18: interleukin 18; IL1A/IL-1α: interleukin 1 alpha; IL1B/IL-1β: interleukin 1 beta; IL22/IL-22: interleukin 22; IL23A: interleukin 23 subunit alpha; IL23R: interleukin 23 receptor; IMQ: imiquimod; ITGAM/CD11B: integrin subunit alpha M; ITGAX/CD11C: integrin subunit alpha X; IVL: involucrin; KC: keratinocyte; KD: knockdown; KO: knockout; Krt14+/+-Atg5f/f mice: mice bearing an Atg5 flox allele, in which exon 3 of the Atg5 gene is flanked by two loxP sites; Krt14+/+-Hmgb1f/f: mice bearing an Hmgb1 flox allele, in which exon 2 to 4 of the Hmgb1 gene is flanked by two loxP sites; Krt14Cre/+-atg5f/f mice: keratinocyte-specific atg5 knockout mice generated by mating Atg5-floxed mice with mice expressing Cre recombinase under the control of the promoter of Krt4; Krt14Cre/+-hmgb1f/f mice: keratinocyte-specific hmgb1 knockout mice generated by mating Hmgb1-floxed mice with mice expressing Cre recombinase under the control of the promoter of Krt14; Krt14-Vegfa mice: mice expressing 164-amino acid Vegfa splice variant recombinase under the control of promoter of Krt14; LAMP1: lysosomal associated membrane protein 1; LDH: lactate dehydrogenase; LORICRIN: loricrin cornified envelope precursor protein; M5: TNF, IL1A, IL17A, IL22 and OSM in combination; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAPK: mitogen-activated protein kinase; MKI67: marker of proliferation Ki-67; MTT: thiazolyl blue tetrazolium bromide; NFKB/NF-κB: nuclear factor kappa B; NHEKs: primary normal human epidermal keratinocytes; NS: not significant; OSM: oncostatin M; PASI: psoriasis area and severity index; PtdIns3K: class III phosphatidylinositol 3-kinase; qRT-PCR: quantitative RT-PCR; RELA/p65: RELA proto-oncogene, NF-kB subunit; rHMGB1: recombinant HMGB1; rIL18: recombinant interleukin 18; rIL1B: recombinant interleukin 1 beta; S100A: S100 calcium binding protein A; SQSTM1/p62: sequestosome 1; T17: IL17A-producing T; TCR: T-cell receptor; tcrd KO mice: tcrd (T cell receptor delta chain) knockout mice, which show deficient receptor expression in all adult lymphoid and epithelial organs; TLR: toll-like receptor; TNF/TNF-α: tumor necrosis factor; WOR: wortmannin; WT: wild-type; γδT17 cells: IL17A-producing γδ T cells.
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Affiliation(s)
- Zhen Wang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Hong Zhou
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Huaping Zheng
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Xikun Zhou
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Guobo Shen
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Xiu Teng
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Xiao Liu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Jun Zhang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Xiaoqiong Wei
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Zhonglan Hu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Fanlian Zeng
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Yawen Hu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Jing Hu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Xiaoyan Wang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Shuwen Chen
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Juan Cheng
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Chen Zhang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Yiyue Gui
- Department of Cardiovascular Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Song Zou
- Department of Cardiovascular Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Yan Hao
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Qixiang Zhao
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Wenling Wu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Yifan Zhou
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Kaijun Cui
- Department of Cardiovascular Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Nongyu Huang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Yuquan Wei
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Wei Li
- Department of Dermatovenereology, West China Hospital, Sichuan University, Chengdu, China
| | - Jiong Li
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
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Phobalysin: Fisheye View of Membrane Perforation, Repair, Chemotaxis and Adhesion. Toxins (Basel) 2019; 11:toxins11070412. [PMID: 31315179 PMCID: PMC6669599 DOI: 10.3390/toxins11070412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/04/2019] [Accepted: 07/11/2019] [Indexed: 11/30/2022] Open
Abstract
Phobalysin P (PhlyP, for photobacterial lysin encoded on a plasmid) is a recently described small β-pore forming toxin of Photobacterium damselae subsp. damselae (Pdd). This organism, belonging to the family of Vibrionaceae, is an emerging pathogen of fish and various marine animals, which occasionally causes life-threatening soft tissue infections and septicemia in humans. By using genetically modified Pdd strains, PhlyP was found to be an important virulence factor. More recently, in vitro studies with purified PhlyP elucidated some basic consequences of pore formation. Being the first bacterial small β-pore forming toxin shown to trigger calcium-influx dependent membrane repair, PhlyP has advanced to a revealing model toxin to study this important cellular function. Further, results from co-culture experiments employing various Pdd strains and epithelial cells together with data on other bacterial toxins indicate that limited membrane damage may generally enhance the association of bacteria with target cells. Thereby, remodeling of plasma membrane and cytoskeleton during membrane repair could be involved. In addition, a chemotaxis-dependent attack-and track mechanism influenced by environmental factors like salinity may contribute to PhlyP-dependent association of Pdd with cells. Obviously, a synoptic approach is required to capture the regulatory links governing the interaction of Pdd with target cells. The characterization of Pdd’s secretome may hold additional clues because it may lead to the identification of proteases activating PhlyP’s pro-form. Current findings on PhlyP support the notion that pore forming toxins are not just killer proteins but serve bacteria to fulfill more subtle functions, like accessing their host.
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Lazzaro M, Krapf D, García Véscovi E. Selective blockage of Serratia marcescens ShlA by nickel inhibits the pore-forming toxin-mediated phenotypes in eukaryotic cells. Cell Microbiol 2019; 21:e13045. [PMID: 31099073 DOI: 10.1111/cmi.13045] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 04/29/2019] [Accepted: 05/08/2019] [Indexed: 12/29/2022]
Abstract
Serratia marcescens is an opportunistic pathogen with increasing incidence in clinical settings. This is mainly attributed to the timely expression of a wide diversity of virulence factors and intrinsic and acquired resistance to antibiotics, including β-lactams, aminoglycosides, quinolones, and polypeptides. For these reasons, S. marcescens has been recently categorised by the World Health Organization as one priority to strengthen efforts directed to develop new antibacterial agents. Therefore, it becomes critical to understand the underlying mechanisms that allow Serratia to succeed within the host. S. marcescens ShlA pore-forming toxin mediates phenotypes that alter homeostatic and signal transduction pathways of host cells. It has been previously demonstrated that ShlA provokes cytotoxicity, haemolysis and autophagy and also directs Serratia egress and dissemination from invaded nonphagocytic cells. However, molecular details of ShlA mechanism of action are still not fully elucidated. In this work, we demonstrate that Ni2+ selectively and reversibly blocks ShlA action, turning wild-type S. marcescens into a shlA mutant strain phenocopy. Combined use of Ni2+ and calcium chelators allow to discern ShlA-triggered phenotypes that require intracellular calcium mobilisation and reveal ShlA function as a calcium channel, providing new insights into ShlA mode of action on target cells.
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Affiliation(s)
- Martina Lazzaro
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Tecnológicas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Darío Krapf
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Tecnológicas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Eleonora García Véscovi
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Tecnológicas, Universidad Nacional de Rosario, Rosario, Argentina
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21
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Brito C, Cabanes D, Sarmento Mesquita F, Sousa S. Mechanisms protecting host cells against bacterial pore-forming toxins. Cell Mol Life Sci 2019; 76:1319-1339. [PMID: 30591958 PMCID: PMC6420883 DOI: 10.1007/s00018-018-2992-8] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 12/06/2018] [Accepted: 12/10/2018] [Indexed: 12/19/2022]
Abstract
Pore-forming toxins (PFTs) are key virulence determinants produced and secreted by a variety of human bacterial pathogens. They disrupt the plasma membrane (PM) by generating stable protein pores, which allow uncontrolled exchanges between the extracellular and intracellular milieus, dramatically disturbing cellular homeostasis. In recent years, many advances were made regarding the characterization of conserved repair mechanisms that allow eukaryotic cells to recover from mechanical disruption of the PM membrane. However, the specificities of the cell recovery pathways that protect host cells against PFT-induced damage remain remarkably elusive. During bacterial infections, the coordinated action of such cell recovery processes defines the outcome of infected cells and is, thus, critical for our understanding of bacterial pathogenesis. Here, we review the cellular pathways reported to be involved in the response to bacterial PFTs and discuss their impact in single-cell recovery and infection.
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Affiliation(s)
- Cláudia Brito
- i3S-Instituto de Investigação e Inovação em Saúde, IBMC, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal
- Programa Doutoral em Biologia Molecular e Celular (MCbiology), Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313, Porto, Portugal
| | - Didier Cabanes
- i3S-Instituto de Investigação e Inovação em Saúde, IBMC, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal
| | - Francisco Sarmento Mesquita
- i3S-Instituto de Investigação e Inovação em Saúde, IBMC, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal.
- Global Health Institute, School of Life Science, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | - Sandra Sousa
- i3S-Instituto de Investigação e Inovação em Saúde, IBMC, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal.
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22
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Kwon SH, Lim CJ, Jung J, Kim HJ, Park K, Shin JW, Huh CH, Park KC, Na JI. The effect of autophagy-enhancing peptide in moisturizer on atopic dermatitis: a randomized controlled trial. J DERMATOL TREAT 2018; 30:558-564. [PMID: 30427231 DOI: 10.1080/09546634.2018.1544407] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Background: Pentasodium tetracarboxymethyl palmitoyl dipeptide-12 (PTPD-12), a newly-synthesized peptide, enhances the autophagy activity, ultimately managing inflammation. Objective: To determine the effect of a new moisturizer containing PTPD-12 as the treatment of mild-to-moderate atopic dermatitis (AD). Methods: In this double-blind, randomized, placebo-controlled trial, 43 patients with mild-to-moderate AD were randomly assigned to either the PTPD-12 or control groups. Evaluations were performed at baseline, week 2, and week 4, including SCORing Atopic Dermatitis (SCORAD) index score, corneometry, trans-epidermal water loss (TEWL), visual analog scale (VAS) for pruritus, 7-point investigator's global assessment (IGA), and collection of adverse events. Results: The PTPD-12 group showed significant improvement with respect to SCORAD score, skin hydration, TEWL, and pruritus at weeks 2 and 4 when compared with baseline. Although the control group showed significant improvement regarding the SCORAD score and skin hydration, no significant change in TEWL or pruritus was demonstrated throughout the study. The mean changes in the SCORAD index score, skin hydration, TEWL, pruritus, and number of patients with improvement in IGA were not statistically different between the two groups. Conclusion: The moisturizer with autophagy-stimulating property provides a good therapeutic option to mild-to-moderate atopic dermatitis by contributing to skin barrier restoration and control of inflammation.
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Affiliation(s)
- Soon Hyo Kwon
- a Department of Dermatology, Seoul National University College of Medicine, Seoul National University Bundang Hospital , Gyeonggi , Korea
| | | | | | | | | | - Jung Won Shin
- a Department of Dermatology, Seoul National University College of Medicine, Seoul National University Bundang Hospital , Gyeonggi , Korea
| | - Chang Hun Huh
- a Department of Dermatology, Seoul National University College of Medicine, Seoul National University Bundang Hospital , Gyeonggi , Korea
| | - Kyoung Chan Park
- a Department of Dermatology, Seoul National University College of Medicine, Seoul National University Bundang Hospital , Gyeonggi , Korea
| | - Jung Im Na
- a Department of Dermatology, Seoul National University College of Medicine, Seoul National University Bundang Hospital , Gyeonggi , Korea
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23
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Kim IJ, Lee J, Oh SJ, Yoon MS, Jang SS, Holland RL, Reno ML, Hamad MN, Maeda T, Chung HJ, Chen J, Blanke SR. Helicobacter pylori Infection Modulates Host Cell Metabolism through VacA-Dependent Inhibition of mTORC1. Cell Host Microbe 2018; 23:583-593.e8. [PMID: 29746831 DOI: 10.1016/j.chom.2018.04.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 03/15/2018] [Accepted: 04/17/2018] [Indexed: 12/15/2022]
Abstract
Helicobacter pylori (Hp) vacuolating cytotoxin (VacA) is a bacterial exotoxin that enters host cells and induces mitochondrial dysfunction. However, the extent to which VacA-dependent mitochondrial perturbations affect overall cellular metabolism is poorly understood. We report that VacA perturbations in mitochondria are linked to alterations in cellular amino acid homeostasis, which results in the inhibition of mammalian target of rapamycin complex 1 (mTORC1) and subsequent autophagy. mTORC1, which regulates cellular metabolism during nutrient stress, is inhibited during Hp infection by a VacA-dependent mechanism. This VacA-dependent inhibition of mTORC1 signaling is linked to the dissociation of mTORC1 from the lysosomal surface and results in activation of cellular autophagy through the Unc 51-like kinase 1 (Ulk1) complex. VacA intoxication results in reduced cellular amino acids, and bolstering amino acid pools prevents VacA-mediated mTORC1 inhibition. Overall, these studies support a model that Hp modulate host cell metabolism through the action of VacA at mitochondria.
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Affiliation(s)
- Ik-Jung Kim
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA
| | - Jeongmin Lee
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - Seung J Oh
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - Mee-Sup Yoon
- Department of Cell and Developmental Biology, University of Illinois, Urbana, IL 61801, USA; Department of Molecular Medicine, School of Medicine, Gachon University, Incheon 406-840, Republic of Korea
| | - Sung-Soo Jang
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana, IL 61801, USA
| | - Robin L Holland
- Department of Pathobiology, University of Illinois, Urbana, IL 61801, USA
| | - Michael L Reno
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA
| | - Mohammed N Hamad
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA
| | - Tatsuya Maeda
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana, IL 61801, USA
| | - Jie Chen
- Department of Cell and Developmental Biology, University of Illinois, Urbana, IL 61801, USA
| | - Steven R Blanke
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA; Institute for Genomic Biology, University of Illinois, Urbana, IL 61801, USA; Lead Contact.
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24
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Mohankumar V, Ramalingam S, Chidambaranathan GP, Prajna L. Autophagy induced by type III secretion system toxins enhances clearance of Pseudomonas aeruginosa from human corneal epithelial cells. Biochem Biophys Res Commun 2018; 503:1510-1515. [DOI: 10.1016/j.bbrc.2018.07.071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 07/13/2018] [Indexed: 10/28/2022]
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25
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Abstract
The association of variants in the APOL1 gene, which encodes apolipoprotein L1 (APOL1), with progressive nondiabetic kidney diseases in African Americans has prompted intense investigation into the function(s) of APOL1. APOL1 is an innate immune effector that protects human beings from infection by some trypanosomal parasites. We review the data characterizing APOL1 trypanolytic function, which has been a basis for studies of APOL1 function in mammalian cells. Subsequently, we discuss the studies that use animal models, mammalian cell culture models, and kidney biopsy tissue to discover the mechanisms of variant APOL1-associated kidney diseases.
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26
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Rodrigues LOCP, Graça RSF, Carneiro LAM. Integrated Stress Responses to Bacterial Pathogenesis Patterns. Front Immunol 2018; 9:1306. [PMID: 29930559 PMCID: PMC5999787 DOI: 10.3389/fimmu.2018.01306] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 05/25/2018] [Indexed: 12/25/2022] Open
Abstract
Activation of an appropriate innate immune response to bacterial infection is critical to limit microbial spread and generate cytokines and chemokines to instruct appropriate adaptive immune responses. Recognition of bacteria or bacterial products by pattern recognition molecules is crucial to initiate this response. However, it is increasingly clear that the context in which this recognition occurs can dictate the quality of the response and determine the outcome of an infection. The cross talk established between host and pathogen results in profound alterations on cellular homeostasis triggering specific cellular stress responses. In particular, the highly conserved integrated stress response (ISR) has been shown to shape the host response to bacterial pathogens by sensing cellular insults resulting from infection and modulating transcription of key genes, translation of new proteins and cell autonomous antimicrobial mechanisms such as autophagy. Here, we review the growing body of evidence demonstrating a role for the ISR as an integral part of the innate immune response to bacterial pathogens.
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Affiliation(s)
- Larissa O C P Rodrigues
- Laboratório de Inflamação e Imunidade, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Rodrigo S F Graça
- Laboratório de Inflamação e Imunidade, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Leticia A M Carneiro
- Laboratório de Inflamação e Imunidade, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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27
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Osborne SE, Brumell JH. Listeriolysin O: from bazooka to Swiss army knife. Philos Trans R Soc Lond B Biol Sci 2018. [PMID: 28630160 DOI: 10.1098/rstb.2016.0222] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Listeria monocytogenes (Lm) is a Gram-positive facultative intracellular pathogen. Infections in humans can lead to listeriosis, a systemic disease with a high mortality rate. One important mechanism of Lm dissemination involves cell-to-cell spread after bacteria have entered the cytosol of host cells. Listeriolysin O (LLO; encoded by the hly gene) is a virulence factor present in Lm that plays a central role in the cell-to-cell spread process. LLO is a member of the cholesterol-dependent cytolysin (CDC) family of toxins that were initially thought to promote disease largely by inducing cell death and tissue destruction-essentially acting like a 'bazooka'. This view was supported by structural studies showing CDCs can form large pores in membranes. However, it is now appreciated that LLO has many subtle activities during Lm infection of host cells, and many of these likely do not involve large pores, but rather small membrane perforations. It is also appreciated that membrane repair pathways of host cells play a major role in limiting membrane damage by LLO and other toxins. LLO is now thought to represent a 'Swiss army knife', a versatile tool that allows Lm to induce many membrane alterations and cellular responses that promote bacterial dissemination during infection.This article is part of the themed issue 'Membrane pores: from structure and assembly, to medicine and technology'.
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Affiliation(s)
- Suzanne E Osborne
- Cell Biology Program, Hospital for Sick Children, Toronto, ON, Canada M5G 1X8
| | - John H Brumell
- Cell Biology Program, Hospital for Sick Children, Toronto, ON, Canada M5G 1X8 .,Sickkids IBD Centre, Hospital for Sick Children, Toronto, ON, Canada M5G 1X8.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada M5S 1A8.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada M5S 1A8
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28
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Xia X, Lei L, Qin W, Wang L, Zhang G, Hu J. GCN2 controls the cellular checkpoint: potential target for regulating inflammation. Cell Death Discov 2018. [PMID: 29531817 PMCID: PMC5841328 DOI: 10.1038/s41420-017-0022-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Xiaojing Xia
- 1College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang, China.,2Postdoctoral Research Base, Henan Institute of Science and Technology, Xinxiang, China.,3Post-doctoral Research Station, Henan Agriculture University, Zhengzhou, China
| | - Liancheng Lei
- 4College of Veterinary Medicine, Jilin University, Changchun, China
| | - Wanhai Qin
- 5Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Lei Wang
- 1College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang, China
| | - Gaiping Zhang
- 3Post-doctoral Research Station, Henan Agriculture University, Zhengzhou, China
| | - Jianhe Hu
- 1College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang, China.,2Postdoctoral Research Base, Henan Institute of Science and Technology, Xinxiang, China
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29
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Balbi T, Cortese K, Ciacci C, Bellese G, Vezzulli L, Pruzzo C, Canesi L. Autophagic processes in Mytilus galloprovincialis hemocytes: Effects of Vibrio tapetis. FISH & SHELLFISH IMMUNOLOGY 2018; 73:66-74. [PMID: 29208501 DOI: 10.1016/j.fsi.2017.12.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 11/29/2017] [Accepted: 12/01/2017] [Indexed: 06/07/2023]
Abstract
Autophagy is a highly conserved and regulated catabolic process involved in maintaining cell homeostasis in response to different stressors. The autophagic machinery is also used as an innate immune mechanism against microbial infection. In invertebrates, that lack acquired immunity, autophagy may thus play a key role in the protection against potential pathogens. In aquatic molluscs, evidence has been provided for induction of autophagy by starvation and different environmental stressors; however, no information is available on autophagic pathways in the immune cells, the hemocytes. In this work, the autophagic processes were investigated in the hemocytes of the marine bivalve, the mussel Mytilus galloprovincialis. The effects of classical inducers/inhibitors of mammalian autophagy were first tested. Rapamycin induced a decrease in lysosomal membrane stability-LMS that was prevented by the autophagy inhibitor Wortmannin. Increased MDC fluorescence and expression of LC3-II were also observed. Moreover, responses to in vitro challenge with the bivalve pathogen Vibrio tapetis were evaluated. Mussel hemocytes were unable to activate the immune response towards V. tapetis; however, bacterial challenge induced a moderate decrease in LMS, corresponding to lysosomal activation but no cytotoxicity; the effect was prevented by Wortmannin. TEM observations showed that V. tapetis resulted in rapid formation of autophagosomes and autolysosomes. Accordingly, increased LC3-II expression, decreased levels of phosphorylated mTor and of p62 were observed. The results represent the first evidence for autophagic processes in bivalve hemocytes in response to bacterial challenge, and underline the protective role of autophagy towards potential pathogenic vibrios.
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Affiliation(s)
- Teresa Balbi
- Dept. of Earth, Environment and Life Sciences (DISTAV), University of Genoa, Italy
| | - Katia Cortese
- Dept. of Experimental Medicine (DIMES), University of Genoa, Italy
| | - Caterina Ciacci
- Dept. of Biomolecular Sciences (DISBM), University of Urbino, Italy
| | - Grazia Bellese
- Dept. of Experimental Medicine (DIMES), University of Genoa, Italy
| | - Luigi Vezzulli
- Dept. of Earth, Environment and Life Sciences (DISTAV), University of Genoa, Italy
| | - Carla Pruzzo
- Dept. of Earth, Environment and Life Sciences (DISTAV), University of Genoa, Italy
| | - Laura Canesi
- Dept. of Earth, Environment and Life Sciences (DISTAV), University of Genoa, Italy.
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30
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Li L, Chen X, Gu H. The signaling involved in autophagy machinery in keratinocytes and therapeutic approaches for skin diseases. Oncotarget 2018; 7:50682-50697. [PMID: 27191982 PMCID: PMC5226613 DOI: 10.18632/oncotarget.9330] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 04/26/2016] [Indexed: 02/06/2023] Open
Abstract
Autophagy is responsible for the lysosomal degradation of proteins, organelles, microorganisms and exogenous particles. Epidermis primarily consists of keratinocytes which functions as an extremely important barrier. Investigation on autophagy in keratinocytes has been continuously renewing, but is not so systematic due to the complexity of the autophagy machinery. Here we reviewed recent studies on the autophagy in keratinocyte with a focus on interplay between autophagy machinery and keratinocytes biology, and novel autophagy regulators identified in keratinocytes. In this review, we discussed the roles of autophagy in apoptosis, differentiation, immune response, survival and melanin metabolism, trying to reveal the possible involvement of autophagy in skin aging, skin disorders and skin color formation. Since autophagy routinely plays a double-edged sword role in various conditions, its functions in skin homeostasis and potential application as a therapeutic target for skin diseases remains to be clarified. Furthermore, more investigations are needed on optimizing designed strategies to inhibit or enhance autophagy for clinical efficacy.
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Affiliation(s)
- Li Li
- Institute of Dermatology, Chinese Academy of Medical Science & Peking Union Medical College, Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China
| | - Xu Chen
- Institute of Dermatology, Chinese Academy of Medical Science & Peking Union Medical College, Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China
| | - Heng Gu
- Institute of Dermatology, Chinese Academy of Medical Science & Peking Union Medical College, Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China
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31
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Moreira D, Silvestre R, Cordeiro-da-Silva A, Estaquier J, Foretz M, Viollet B. AMP-activated Protein Kinase As a Target For Pathogens: Friends Or Foes? Curr Drug Targets 2017; 17:942-53. [PMID: 25882224 DOI: 10.2174/1389450116666150416120559] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 03/24/2015] [Accepted: 04/10/2015] [Indexed: 12/21/2022]
Abstract
Intracellular pathogens are known to manipulate host cell regulatory pathways to establish an optimal environment for their growth and survival. Pathogens employ active mechanisms to hijack host cell metabolism and acquire existing nutrient and energy store. The role of the cellular energy sensor AMP-activated protein kinase (AMPK) in the regulation of cellular energy homeostasis is well documented. Here, we highlight recent advances showing the importance of AMPK signaling in pathogen-host interactions. Pathogens interact with AMPK by a variety of mechanisms aimed at reprogramming host cell metabolism to their own benefit. Stimulation of AMPK activity provides an efficient process to rapidly adapt pathogen metabolism to the major nutritional changes often encountered during the different phases of infection. However, inhibition of AMPK is also used by pathogens to manipulate innate host response, indicating that AMPK appears relevant to restriction of pathogen infection. We also document the effects of pharmacological AMPK modulators on pathogen proliferation and survival. This review illustrates intricate pathogen-AMPK interactions that may be exploited to the development of novel anti-pathogen therapies.
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Affiliation(s)
| | | | | | | | | | - Benoit Viollet
- Institut Cochin, Inserm U1016, CNRS UMR8104, Université Paris Descartes, 24 rue du faubourg Saint Jacques 75014 Paris, France.
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32
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Glucosyltransferase Activity of Clostridium difficile Toxin B Triggers Autophagy-mediated Cell Growth Arrest. Sci Rep 2017; 7:10532. [PMID: 28874882 PMCID: PMC5585374 DOI: 10.1038/s41598-017-11336-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 07/04/2017] [Indexed: 12/19/2022] Open
Abstract
Autophagy is a bulk cell-degradation process that occurs through the lysosomal machinery, and many reports have shown that it participates in microbial pathogenicity. However, the role of autophagy in Clostridium difficile infection (CDI), the leading cause of antibiotics-associated diarrhea, pseudomembranous colitis and even death in severe cases, is not clear. Here we report that the major virulent factor toxin B (TcdB) of Clostridium difficile elicits a strong autophagy response in host cells through its glucosyltransferase activity. Using a variety of autophagy-deficient cell lines, i.e. HeLa/ATG7−/−, MEF/atg7−/−, MEF/tsc2−/−, we demonstrate that toxin-triggered autophagy inhibits host cell proliferation, which contributes to TcdB-caused cytopathic biological effects. We further show that both the PI3K complex and mTOR pathway play important roles in this autophagy induction process and consequent cytopathic event. Although the glucosyltransferase activity of TcdB is responsible for inducing both cell rounding and autophagy, there is no evidence suggesting the causal relationship between these two events. Taken together, our data demonstrate for the first time that the glucosyltransferase enzymatic activity of a pathogenic bacteria is responsible for host autophagy induction and the following cell growth arrest, providing a new paradigm for the role of autophagy in host defense mechanisms upon pathogenic infection.
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33
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Vdovikova S, Luhr M, Szalai P, Nygård Skalman L, Francis MK, Lundmark R, Engedal N, Johansson J, Wai SN. A Novel Role of Listeria monocytogenes Membrane Vesicles in Inhibition of Autophagy and Cell Death. Front Cell Infect Microbiol 2017; 7:154. [PMID: 28516064 PMCID: PMC5413512 DOI: 10.3389/fcimb.2017.00154] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/12/2017] [Indexed: 11/13/2022] Open
Abstract
Bacterial membrane vesicle (MV) production has been mainly studied in Gram-negative species. In this study, we show that Listeria monocytogenes, a Gram-positive pathogen that causes the food-borne illness listeriosis, produces MVs both in vitro and in vivo. We found that a major virulence factor, the pore-forming hemolysin listeriolysin O (LLO), is tightly associated with the MVs, where it resides in an oxidized, inactive state. Previous studies have shown that LLO may induce cell death and autophagy. To monitor possible effects of LLO and MVs on autophagy, we performed assays for LC3 lipidation and LDH sequestration as well as analysis by confocal microscopy of HEK293 cells expressing GFP-LC3. The results revealed that MVs alone did not affect autophagy whereas they effectively abrogated autophagy induced by pure LLO or by another pore-forming toxin from Vibrio cholerae, VCC. Moreover, Listeria monocytogenes MVs significantly decreased Torin1-stimulated macroautophagy. In addition, MVs protected against necrosis of HEK293 cells caused by the lytic action of LLO. We explored the mechanisms of LLO-induced autophagy and cell death and demonstrated that the protective effect of MVs involves an inhibition of LLO-induced pore formation resulting in inhibition of autophagy and the lytic action on eukaryotic cells. Further, we determined that these MVs help bacteria to survive inside eukaryotic cells (mouse embryonic fibroblasts). Taken together, these findings suggest that intracellular release of MVs from L. monocytogenes may represent a bacterial strategy to survive inside host cells, by its control of LLO activity and by avoidance of destruction from the autophagy system during infection.
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Affiliation(s)
- Svitlana Vdovikova
- Department of Molecular Biology, Umeå UniversityUmeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden, Umeå UniversityUmeå, Sweden.,Umeå Centre for Microbial Research, Umeå UniversityUmeå, Sweden
| | - Morten Luhr
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of OsloOslo, Norway
| | - Paula Szalai
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of OsloOslo, Norway
| | - Lars Nygård Skalman
- Laboratory for Molecular Infection Medicine Sweden, Umeå UniversityUmeå, Sweden.,Department of Medical Biochemistry and Biophysics, Umeå UniversityUmeå, Sweden
| | - Monika K Francis
- Laboratory for Molecular Infection Medicine Sweden, Umeå UniversityUmeå, Sweden.,Department of Medical Biochemistry and Biophysics, Umeå UniversityUmeå, Sweden
| | - Richard Lundmark
- Laboratory for Molecular Infection Medicine Sweden, Umeå UniversityUmeå, Sweden.,Department of Medical Biochemistry and Biophysics, Umeå UniversityUmeå, Sweden.,Department of Integrative Medical Biology, Umeå UniversityUmeå, Sweden
| | - Nikolai Engedal
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of OsloOslo, Norway
| | - Jörgen Johansson
- Department of Molecular Biology, Umeå UniversityUmeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden, Umeå UniversityUmeå, Sweden.,Umeå Centre for Microbial Research, Umeå UniversityUmeå, Sweden
| | - Sun N Wai
- Department of Molecular Biology, Umeå UniversityUmeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden, Umeå UniversityUmeå, Sweden.,Umeå Centre for Microbial Research, Umeå UniversityUmeå, Sweden
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34
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Dissecting the role of ADAM10 as a mediator of Staphylococcus aureus α-toxin action. Biochem J 2016; 473:1929-40. [DOI: 10.1042/bcj20160062] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 04/28/2016] [Indexed: 01/26/2023]
Abstract
This work elucidates the role of the transmembrane protease ADAM10 (a disintegrin and metalloprotease 10) for the action of Staphylococcus aureus α-toxin, by showing that the cytotoxicity of α-toxin does not depend on ADAM10’s catalytic activity but on the chaperone function of its prodomain.
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35
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Statt S, Ruan JW, Hung LY, Chang CY, Huang CT, Lim JH, Li JD, Wu R, Kao CY. Statin-conferred enhanced cellular resistance against bacterial pore-forming toxins in airway epithelial cells. Am J Respir Cell Mol Biol 2016; 53:689-702. [PMID: 25874372 DOI: 10.1165/rcmb.2014-0391oc] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Statins are widely used to prevent cardiovascular disease. In addition to their inhibitory effects on cholesterol synthesis, statins have beneficial effects in patients with sepsis and pneumonia, although molecular mechanisms have mostly remained unclear. Using human airway epithelial cells as a proper in vitro model, we show that prior exposure to physiological nanomolar serum concentrations of simvastatin (ranging from 10-1,000 nM) confers significant cellular resistance to the cytotoxicity of pneumolysin, a pore-forming toxin and the main virulence factor of Streptococcus pneumoniae. This protection could be demonstrated with a different statin, pravastatin, or on a different toxin, α-hemolysin. Furthermore, through the use of gene silencing, pharmacological inhibitors, immunofluorescence microscopy, and biochemical and metabolic rescue approaches, we demonstrate that the mechanism of protection conferred by simvastatin at physiological nanomolar concentrations could be different from the canonical mevalonate pathways seen in most other mechanistic studies conducted with statins at micromolar levels. All of these data are integrated into a protein synthesis-dependent, calcium-dependent model showing the interconnected pathways used by statins in airway epithelial cells to elicit an increased resistance to pore-forming toxins. This research fills large gaps in our understanding of how statins may confer host cellular protection against bacterial infections in the context of airway epithelial cells without the confounding effect from the presence of immune cells. In addition, our discovery could be potentially developed into a host-centric strategy for the adjuvant treatment of pore-forming toxin associated bacterial infections.
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Affiliation(s)
- Sarah Statt
- 1 Center for Comparative Respiratory Biology and Medicine, University of California at Davis, Davis, California
| | - Jhen-Wei Ruan
- 2 Immunology Research Center, National Health Research Institutes, Zhunan, Miaoli, Taiwan
| | - Li-Yin Hung
- 1 Center for Comparative Respiratory Biology and Medicine, University of California at Davis, Davis, California
| | - Ching-Yun Chang
- 1 Center for Comparative Respiratory Biology and Medicine, University of California at Davis, Davis, California
| | - Chih-Ting Huang
- 2 Immunology Research Center, National Health Research Institutes, Zhunan, Miaoli, Taiwan
| | - Jae Hyang Lim
- 3 Department of Microbiology, Ewha Womans University School of Medicine, Seoul, Korea; and
| | - Jian-Dong Li
- 4 Center for Inflammation, Immunity & Infection, Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia
| | - Reen Wu
- 1 Center for Comparative Respiratory Biology and Medicine, University of California at Davis, Davis, California
| | - Cheng-Yuan Kao
- 1 Center for Comparative Respiratory Biology and Medicine, University of California at Davis, Davis, California.,2 Immunology Research Center, National Health Research Institutes, Zhunan, Miaoli, Taiwan
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36
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Mesquita I, Moreira D, Sampaio-Marques B, Laforge M, Cordeiro-da-Silva A, Ludovico P, Estaquier J, Silvestre R. AMPK in Pathogens. EXPERIENTIA SUPPLEMENTUM (2012) 2016; 107:287-323. [PMID: 27812985 DOI: 10.1007/978-3-319-43589-3_12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
During host-pathogen interactions, a complex web of events is crucial for the outcome of infection. Pathogen recognition triggers powerful cellular signaling events that is translated into the induction and maintenance of innate and adaptive host immunity against infection. In opposition, pathogens employ active mechanisms to manipulate host cell regulatory pathways toward their proliferation and survival. Among these, subversion of host cell energy metabolism by pathogens is currently recognized to play an important role in microbial growth and persistence. Extensive studies have documented the role of AMP-activated protein kinase (AMPK) signaling, a central cellular hub involved in the regulation of energy homeostasis, in host-pathogen interactions. Here, we highlight the most recent advances detailing how pathogens hijack cellular metabolism by suppressing or increasing the activity of the host energy sensor AMPK. We also address the role of lower eukaryote AMPK orthologues in the adaptive process to the host microenvironment and their contribution for pathogen survival, differentiation, and growth. Finally, we review the effects of pharmacological or genetic AMPK modulation on pathogen growth and persistence.
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Affiliation(s)
- Inês Mesquita
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.,ICVS/3Bs-PT Government Associate Laboratory, Guimarães, Braga, Portugal
| | - Diana Moreira
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Belém Sampaio-Marques
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.,ICVS/3Bs-PT Government Associate Laboratory, Guimarães, Braga, Portugal
| | | | - Anabela Cordeiro-da-Silva
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Paula Ludovico
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.,ICVS/3Bs-PT Government Associate Laboratory, Guimarães, Braga, Portugal
| | - Jérôme Estaquier
- CNRS FR 3636, Université Paris Descartes, Paris, France.,Centre de Recherche du CHU de Québec, Université Laval, Québec, QC, Canada
| | - Ricardo Silvestre
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal. .,ICVS/3Bs-PT Government Associate Laboratory, Guimarães, Braga, Portugal.
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37
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The ever-emerging complexity of α-toxin's interaction with host cells. Proc Natl Acad Sci U S A 2015; 112:14123-4. [PMID: 26542682 DOI: 10.1073/pnas.1519766112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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Phobalysin, a Small β-Pore-Forming Toxin of Photobacterium damselae subsp. damselae. Infect Immun 2015; 83:4335-48. [PMID: 26303391 DOI: 10.1128/iai.00277-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 08/15/2015] [Indexed: 12/16/2022] Open
Abstract
Photobacterium damselae subsp. damselae, an important pathogen of marine animals, may also cause septicemia or hyperaggressive necrotizing fasciitis in humans. We previously showed that hemolysin genes are critical for virulence of this organism in mice and fish. In the present study, we characterized the hlyA gene product, a putative small β-pore-forming toxin, and termed it phobalysin P (PhlyP), for "photobacterial lysin encoded on a plasmid." PhlyP formed stable oligomers and small membrane pores, causing efflux of K(+), with no significant leakage of lactate dehydrogenase but entry of vital dyes. The latter feature distinguished PhlyP from the related Vibrio cholerae cytolysin. Attack by PhlyP provoked a loss of cellular ATP, attenuated translation, and caused profound morphological changes in epithelial cells. In coculture experiments with epithelial cells, Photobacterium damselae subsp. damselae led to rapid hemolysin-dependent membrane permeabilization. Unexpectedly, hemolysins also promoted the association of P. damselae subsp. damselae with epithelial cells. The collective observations of this study suggest that membrane-damaging toxins commonly enhance bacterial adherence.
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Khilwani B, Chattopadhyay K. Signaling beyond Punching Holes: Modulation of Cellular Responses by Vibrio cholerae Cytolysin. Toxins (Basel) 2015; 7:3344-58. [PMID: 26308054 PMCID: PMC4549754 DOI: 10.3390/toxins7083344] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 08/12/2015] [Accepted: 08/14/2015] [Indexed: 01/20/2023] Open
Abstract
Pore-forming toxins (PFTs) are a distinct class of membrane-damaging cytolytic proteins that contribute significantly towards the virulence processes employed by various pathogenic bacteria. Vibrio cholerae cytolysin (VCC) is a prominent member of the beta-barrel PFT (beta-PFT) family. It is secreted by most of the pathogenic strains of the intestinal pathogen V. cholerae. Owing to its potent membrane-damaging cell-killing activity, VCC is believed to play critical roles in V. cholerae pathogenesis, particularly in those strains that lack the cholera toxin. Large numbers of studies have explored the mechanistic basis of the cell-killing activity of VCC. Consistent with the beta-PFT mode of action, VCC has been shown to act on the target cells by forming transmembrane oligomeric beta-barrel pores, thereby leading to permeabilization of the target cell membranes. Apart from the pore-formation-induced direct cell-killing action, VCC exhibits the potential to initiate a plethora of signal transduction pathways that may lead to apoptosis, or may act to enhance the cell survival/activation responses, depending on the type of target cells. In this review, we will present a concise view of our current understanding regarding the multiple aspects of these cellular responses, and their underlying signaling mechanisms, evoked by VCC.
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Affiliation(s)
- Barkha Khilwani
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences Indian Institute of Science Education and Research Mohali Sector 81, S. A. S. Nagar, Manauli PO 140306, Punjab, India.
| | - Kausik Chattopadhyay
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences Indian Institute of Science Education and Research Mohali Sector 81, S. A. S. Nagar, Manauli PO 140306, Punjab, India.
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Interactions between Autophagy and Bacterial Toxins: Targets for Therapy? Toxins (Basel) 2015; 7:2918-58. [PMID: 26248079 PMCID: PMC4549733 DOI: 10.3390/toxins7082918] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 07/27/2015] [Accepted: 07/28/2015] [Indexed: 01/07/2023] Open
Abstract
Autophagy is a physiological process involved in defense mechanisms for clearing intracellular bacteria. The autophagic pathway is finely regulated and bacterial toxins interact with this process in a complex manner. Bacterial toxins also interact significantly with many biochemical processes. Evaluations of the effects of bacterial toxins, such as endotoxins, pore-forming toxins and adenylate cyclases, on autophagy could support the development of new strategies for counteracting bacterial pathogenicity. Treatment strategies could focus on drugs that enhance autophagic processes to improve the clearance of intracellular bacteria. However, further in vivo studies are required to decipher the upregulation of autophagy and potential side effects limiting such approaches. The capacity of autophagy activation strategies to improve the outcome of antibiotic treatment should be investigated in the future.
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von Hoven G, Neukirch C, Meyenburg M, Füser S, Petrivna MB, Rivas AJ, Ryazanov A, Kaufman RJ, Aroian RV, Husmann M. eIF2α Confers Cellular Tolerance to S. aureus α-Toxin. Front Immunol 2015; 6:383. [PMID: 26284068 PMCID: PMC4515601 DOI: 10.3389/fimmu.2015.00383] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 07/13/2015] [Indexed: 11/13/2022] Open
Abstract
We report on the role of conserved stress-response pathways for cellular tolerance to a pore forming toxin. First, we observed that small molecular weight inhibitors including of eIF2α-phosphatase, jun-N-terminal kinase (JNK), and PI3-kinase sensitized normal mouse embryonal fibroblasts (MEFs) to the small pore forming S. aureus α-toxin. Sensitization depended on expression of mADAM10, the murine ortholog of a proposed high-affinity receptor for α-toxin in human cells. Similarly, eIF2α (S51A/S51A) MEFs, which harbor an Ala knock-in mutation at the regulated Ser51 phosphorylation site of eukaryotic translation initiation factor 2α, were hyper-sensitive to α-toxin. Inhibition of translation with cycloheximide did not mimic the tolerogenic effect of eIF2α-phosphorylation. Notably, eIF2α-dependent tolerance of MEFs was toxin-selective, as wild-type MEFs and eIF2α (S51A/S51A) MEFs exhibited virtually equal sensitivity to Vibrio cholerae cytolysin. Binding of S. aureus α-toxin to eIF2α (S51A/S51A) MEFs and toxicity in these cells were enhanced as compared to wild-type cells. This led to the unexpected finding that the mutant cells carried more ADAM10. Because basal phosphorylation of eIF2α in MEFs required amino acid deprivation-activated eIF2α-kinase 4/GCN2, the data reveal that basal activity of this kinase mediates tolerance of MEFs to α-toxin. Further, they suggest that modulation of ADAM10 is involved. During infection, bacterial growth may cause nutrient shortage in tissues, which might activate this response. Tolerance to α-toxin was robust in macrophages and did not depend on GCN2. However, JNKs appeared to play a role, suggesting differential cell type and toxin selectivity of tolerogenic stress responses. Understanding their function or failure will be important to comprehend anti-bacterial immune responses.
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Affiliation(s)
- Gisela von Hoven
- University Medical Center, Institute of Medical Microbiology and Hygiene, Johannes Gutenberg-University , Mainz , Germany
| | - Claudia Neukirch
- University Medical Center, Institute of Medical Microbiology and Hygiene, Johannes Gutenberg-University , Mainz , Germany
| | - Martina Meyenburg
- University Medical Center, Institute of Medical Microbiology and Hygiene, Johannes Gutenberg-University , Mainz , Germany
| | - Sabine Füser
- University Medical Center, Institute of Medical Microbiology and Hygiene, Johannes Gutenberg-University , Mainz , Germany
| | - Maria Bidna Petrivna
- University Medical Center, Institute of Medical Microbiology and Hygiene, Johannes Gutenberg-University , Mainz , Germany
| | - Amable J Rivas
- University Medical Center, Institute of Medical Microbiology and Hygiene, Johannes Gutenberg-University , Mainz , Germany
| | - Alexey Ryazanov
- Department of Pharmacology, Rutgers Robert Wood Johnson Medical School , Piscataway, NJ , USA
| | - Randal J Kaufman
- Degenerative Diseases Program, Sanford-Burnham Medical Research Institute , La Jolla, CA , USA
| | - Raffi V Aroian
- University of Massachusetts Medical School , Worcester, MA , USA
| | - Matthias Husmann
- University Medical Center, Institute of Medical Microbiology and Hygiene, Johannes Gutenberg-University , Mainz , Germany
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42
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Heneghan JF, Vandorpe DH, Shmukler BE, Giovinazzo JA, Giovinnazo JA, Raper J, Friedman DJ, Pollak MR, Alper SL. BH3 domain-independent apolipoprotein L1 toxicity rescued by BCL2 prosurvival proteins. Am J Physiol Cell Physiol 2015; 309:C332-47. [PMID: 26108665 DOI: 10.1152/ajpcell.00142.2015] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 06/18/2015] [Indexed: 12/12/2022]
Abstract
The potent trypanolytic properties of human apolipoprotein L1 (APOL1) can be neutralized by the trypanosome variant surface antigen gene product known as serum resistance-associated protein. However, two common APOL1 haplotypes present uniquely in individuals of West African ancestry each encode APOL1 variants resistant to serum resistance-associated protein, and each confers substantial resistance to human African sleeping sickness. In contrast to the dominantly inherited anti-trypanosomal activity of APOL1, recessive inheritance of these two trypanoprotective APOL1 alleles predisposes to kidney disease. Proposed mechanisms of APOL1 toxicity have included BH3 domain-dependent autophagy and/or ion channel activity. We probed these potential mechanisms by expressing APOL1 in Xenopus laevis oocytes. APOL1 expression in oocytes increased ion permeability and caused profound morphological deterioration (toxicity). Coexpression of BCL2 family members rescued APOL1-associated oocyte toxicity in the order MCL1 ∼ BCLW > BCLXL ∼ BCL2A1 ≫ BCL2. Deletion of nine nominal core BH3 domain residues abolished APOL1-associated toxicity, but missense substitution of the same residues abolished neither oocyte toxicity nor its rescue by coexpressed MCL1. The APOL1 BH3 domain was similarly dispensable for the ability of APOL1 to rescue intact mice from lethal trypanosome challenge. Replacement of most extracellular Na(+) by K(+) also reduced APOL1-associated oocyte toxicity, allowing demonstration of APOL1-associated increases in Ca(2+) and Cl(-) fluxes and oocyte ion currents, which were similarly reduced by MCL1 coexpression. Thus APOL1 toxicity in Xenopus oocytes is BH3-independent, but can nonetheless be rescued by some BCL2 family proteins.
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Affiliation(s)
- J F Heneghan
- Renal Division, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Department of Medicine, Harvard Medical School, Boston, Massachusetts; and
| | - D H Vandorpe
- Renal Division, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Department of Medicine, Harvard Medical School, Boston, Massachusetts; and
| | - B E Shmukler
- Renal Division, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Department of Medicine, Harvard Medical School, Boston, Massachusetts; and
| | | | - J A Giovinnazo
- The Graduate Center and Department of Biological Sciences, Hunter College of the City University of New York, New York, New York
| | - J Raper
- The Graduate Center and Department of Biological Sciences, Hunter College of the City University of New York, New York, New York
| | - D J Friedman
- Renal Division, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Department of Medicine, Harvard Medical School, Boston, Massachusetts; and
| | - M R Pollak
- Renal Division, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Department of Medicine, Harvard Medical School, Boston, Massachusetts; and
| | - S L Alper
- Renal Division, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Department of Medicine, Harvard Medical School, Boston, Massachusetts; and
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Abstract
Skin is the most common site of Staphylococcus aureus infection. While most of these infections are self-limited, recurrent infections are common. Keratinocytes and recruited immune cells participate in skin defense against infection. We postulated that S. aureus is able to adapt to the milieu within human keratinocytes to avoid keratinocyte-mediated clearance. From a collection of S. aureus isolated from chronically infected patients with atopic dermatitis, we noted 22% had an agr mutant-like phenotype. Using several models of human skin infection, we demonstrate that toxin-deficient, agr mutants of methicillin-resistant S. aureus (MRSA) USA300 are able to persist within keratinocytes by stimulating autophagy and evading caspase-1 and inflammasome activation. MRSA infection induced keratinocyte autophagy, as evidenced by galectin-8 and LC3 accumulation. Autophagy promoted the degradation of inflammasome components and facilitated staphylococcal survival. The recovery of more than 58% agr or RNAIII mutants (P < 0.0001) of an inoculum of wild-type (WT) MRSA from within wortmannin-treated keratinocytes compared to control keratinocytes reflected the survival advantage for mutants no longer expressing agr-dependent toxins. Our results illustrate the dynamic interplay between S. aureus and keratinocytes that can result in the selection of mutants that have adapted specifically to evade keratinocyte-mediated clearance mechanisms. Human skin is a major site of staphylococcal infection, and keratinocytes actively participate in eradication of these pathogens. We demonstrate that methicillin-resistant Staphylococcus aureus (MRSA) is ingested by keratinocytes and activates caspase-1-mediated clearance through pyroptosis. Toxin-deficient MRSA mutants are selected within keratinocytes that fail to induce caspase-1 activity and keratinocyte-mediated clearance. These intracellular staphylococci induce autophagy that enhances their intracellular survival by diminishing inflammasome components. These findings suggest that S. aureus mutants, by exploiting autophagy, can persist within human keratinocytes.
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Abstract
The autophagy pathway represents an evolutionarily conserved cell recycling process that is activated in response to nutrient deprivation and other stress signals. Over the years, it has been linked to an array of cellular functions. Equally, a wide range of cell-intrinsic, as well as extracellular, factors have been implicated in the induction of the autophagy pathway. Microbial infections represent one such factor that can not only activate autophagy through specific mechanisms but also manipulate the response to the invading microbe’s advantage. Moreover, in many cases, particularly among viruses, the pathway has been shown to be intricately involved in the replication cycle of the pathogen. Conversely, autophagy also plays a role in combating the infection process, both through direct destruction of the pathogen and as one of the key mediating factors in the host defense mechanisms of innate and adaptive immunity. Further, the pathway also plays a role in controlling the pathogenesis of infectious diseases by regulating inflammation. In this review, we discuss various interactions between pathogens and the cellular autophagic response and summarize the immunological functions of the autophagy pathway.
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Affiliation(s)
- Mayura Desai
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX, USA
| | - Rong Fang
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX, USA
| | - Jiaren Sun
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX, USA
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Hildebrandt JP. Pore-forming virulence factors of Staphylococcus aureus destabilize epithelial barriers-effects of alpha-toxin in the early phases of airway infection. AIMS Microbiol 2015. [DOI: 10.3934/microbiol.2015.1.11] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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Sorbara MT, Girardin SE. Emerging themes in bacterial autophagy. Curr Opin Microbiol 2014; 23:163-70. [PMID: 25497773 DOI: 10.1016/j.mib.2014.11.020] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 11/25/2014] [Accepted: 11/26/2014] [Indexed: 10/24/2022]
Abstract
The role of autophagy in the control of intracellular bacterial pathogens, also known as xenophagy, is well documented. Here, we highlight recent advances in the field of xenophagy. We review the importance of bacterial targeting by ubiquitination, diacylglycerol (DAG) or proteins such as Nod1, Nod2, NDP52, p62, NBR1, optineurin, LRSAM1 and parkin in the process of xenophagy. The importance of metabolic sensors, such as mTOR and AMPK, in xenophagy induction is also discussed. We also review the in vitro and in vivo evidence that demonstrate a global role for xenophagy in the control of bacterial growth. Finally, the mechanisms evolved by bacteria to escape xenophagy are presented.
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Affiliation(s)
- Matthew T Sorbara
- Department of Immunology, University of Toronto, Toronto M5S 1A8, Canada
| | - Stephen E Girardin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto M5S 1A8, Canada.
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Fader CM, Aguilera MO, Colombo MI. Autophagy response: manipulating the mTOR-controlled machinery by amino acids and pathogens. Amino Acids 2014; 47:2101-12. [PMID: 25234192 DOI: 10.1007/s00726-014-1835-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 09/03/2014] [Indexed: 02/06/2023]
Abstract
Macroautophagy is a self-degradative process that normally maintains cellular homeostasis via a lysosomal pathway. It is induced by different stress signals, including nutrients and growth factors' restriction as well as pathogen invasions. These stimuli are modulated by the serine/threonine protein kinase mammalian target of rapamycin (mTOR) which control not only autophagy but also protein translation and gene expression. This review focuses on the important role of mTOR as a master regulator of cell growth and the autophagy pathway. Here, we have discussed the role of intracellular amino acid availability and intracellular pH in the redistribution of autophagic structures, which may contribute to mammalian target of rapamycin complex 1 (mTORC1) activity regulation. We have also discussed that mTORC1 complex and components of the autophagy machinery are localized at the lysosomal surface, representing a fascinating mechanism to control the metabolism, cellular clearance and also to restrain invading intracellular pathogens.
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Affiliation(s)
- Claudio Marcelo Fader
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología (IHEM)-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Casilla de Correo 56, Centro Universitario, Parque General San Martín, (5500), Mendoza, Argentina
| | - Milton Osmar Aguilera
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología (IHEM)-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Casilla de Correo 56, Centro Universitario, Parque General San Martín, (5500), Mendoza, Argentina
| | - María Isabel Colombo
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología (IHEM)-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Casilla de Correo 56, Centro Universitario, Parque General San Martín, (5500), Mendoza, Argentina.
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Serratia marcescens ShlA pore-forming toxin is responsible for early induction of autophagy in host cells and is transcriptionally regulated by RcsB. Infect Immun 2014; 82:3542-54. [PMID: 24914224 DOI: 10.1128/iai.01682-14] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Serratia marcescens is a Gram-negative bacterium that thrives in a wide variety of ambient niches and interacts with an ample range of hosts. As an opportunistic human pathogen, it has increased its clinical incidence in recent years, being responsible for life-threatening nosocomial infections. S. marcescens produces numerous exoproteins with toxic effects, including the ShlA pore-forming toxin, which has been catalogued as its most potent cytotoxin. However, the regulatory mechanisms that govern ShlA expression, as well as its action toward the host, have remained unclear. We have shown that S. marcescens elicits an autophagic response in host nonphagocytic cells. In this work, we determine that the expression of ShlA is responsible for the autophagic response that is promoted prior to bacterial internalization in epithelial cells. We show that a strain unable to express ShlA is no longer able to induce this autophagic mechanism, while heterologous expression of ShlA/ShlB suffices to confer on noninvasive Escherichia coli the capacity to trigger autophagy. We also demonstrate that shlBA harbors a binding motif for the RcsB regulator in its promoter region. RcsB-dependent control of shlBA constitutes a feed-forward regulatory mechanism that allows interplay with flagellar-biogenesis regulation. At the top of the circuit, activated RcsB downregulates expression of flagella by binding to the flhDC promoter region, preventing FliA-activated transcription of shlBA. Simultaneously, RcsB interaction within the shlBA promoter represses ShlA expression. This circuit offers multiple access points to fine-tune ShlA production. These findings also strengthen the case for an RcsB role in orchestrating the expression of Serratia virulence factors.
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The emerging role of mTOR signalling in antibacterial immunity. Immunol Cell Biol 2014; 92:346-53. [PMID: 24518980 DOI: 10.1038/icb.2014.3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 12/17/2013] [Accepted: 12/18/2013] [Indexed: 12/14/2022]
Abstract
Mammalian target of rapamycin (mTOR) is a central regulator of cellular metabolic homeostasis that is highly conserved in evolution. Recent evidence has revealed the existence of a complex interplay between mTOR signalling and immunity. We review here the emerging role of mTOR signalling in the regulation of Toll-like receptor-dependent innate responses and in the activation of T cells and antigen-presenting cells. We also highlight the importance of amino-acid starvation-driven mTOR inhibition in the control of autophagy and intracellular bacterial clearance.
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Abstract
The cell membrane is crucial for protection of the cell from its environment. MACPF/CDC proteins are a large superfamily known to be essential for bacterial pathogenesis and proper functioning of the immune system. The three most studied groups of MACPF/CDC proteins are cholesterol-dependent cytolysins from bacteria, the membrane attack complex of complement and human perforin. Their primary function is to form transmembrane pores in target cell membranes. The common mechanism of action comprises water-soluble monomeric proteins binding to the host cell membrane, oligomerization, and formation of a functional pore. This causes a disturbance in gradients of ions and other molecules across the membrane and can lead to cell death. Cells react to this form of attack in a complex manner. Responses can be general, like removing the perforated part of the membrane, or more specific, in many cases depending on binding of proteins to specific receptors to trigger various signalling cascades.
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